The rapidly increasing sophistication of recombinant DNA technology is greatly facilitating research and development in the medical and allied health fields. This is particularly the case in the area of cell regulation leading to a greater understanding of the events leading to or involved in cancer, development of acquired immunodeficiency disease syndrome (AIDS), neurological disorders, heart disease, tissue graft rejection and infertility amongst many other conditions.
Two particularly important classes of molecules are the proteinases and kinases.
Proteinases play important roles in a number of physiological and pathological processes such as proteolytic cascades involved in blood coagulation, fibrinolysis and complement activation as well as cleavage of growth factors, hormones and receptors, the release of bioactive molecules and processes involving cell proliferation and development, inflammation, tumour growth and metastasis. Of particular significance are the cellular proteinases, or those proteinases synthesized in cells and tissues which serve to activate or deactivate proteins responsible for performing specific functions. These proteinases may be found outside the cell, within the cell or may be present on the cell surface.
Serine proteinases are particularly important. These proteinases are characterised by a mechanism involving serine, histidine and aspartate amino acids in the serine proteinase active site. Members of the serine proteinase family which play important roles in a range of cellular functions and which have demonstrated causative roles in human diseases include tissue-type plasminogen activator and thrombin (thrombosis and blood clotting), urokinase-type plasminogen activator (cancer and metastasis), trypsin and elastase (emphysema and liver disease) and angiotensin converting enzyme (hypertension).
A serine proteinase is also implicated in TNFα degradation and soluble TNF-receptor (p75) release by THP1 cells (Vey, et al. Eur. J. Imm. 26, 2404-2409, 1996). Serine proteinases have been implicated in the activation of macrophages (Nakabo et al. J. Leukocyte Biol. 60, 328-336, 1996), in nuclear laminin degradation in apoptosis (McConkey et al. J. Biol. Chem., 271, 22398-22406, 1996), in prostaglandin-E2 induced release of soluble TNF receptor shedding (Choi, et al, Cellular Immunology 178-1 Immunol. 24, 3131-3139, 1994), and in the proteolysis of IkB, a regulatory molecule important in signal transduction and apoptosis. Release of serine proteinases known as granzymes is central to CTL killing and many of the substrates cleaved by granzymes are also cleaved by cellular proteinases (for example, IL-1β is a substrate for Granzyme B as well as the cysteine proteinase, interleukin 1β-converting enzyme (ICE)). Granzyme A, a serine proteinase with Arg-amidolytic activity, has been reported to induce the production of IL-6 and IL-8 in lung fibroblasts (Sower et al. Cellular Immunology 171, 159-163, 1996) and cleaves IL1β to a 17 kD mature form that is biologically active.
Kinases are a large group of molecules, many of which regulate the response of cells to external stimuli. These molecules regulate proliferation and differentiation in eukaryotic cells frequently via signal transduction pathways.
The identification of new serine proteinases and kinases permits the development of a range of derivatives, agonists and antagonists at the nucleic acid and protein levels which in turn have applications in the treatment and diagnosis of a range of conditions such as cancer, inflammation, neurological disorders amongst many other conditions including conditions which initiate or promote apoptosis such as viral infection, old age and drug abuse. One particularly useful serine proteinase HELA2 (testisin) identified in accordance with the present invention is involved in spermatogenesis, testicular cancer and as a marker for cancer.